I have a 2005 C240 and the alarm recently will go off for no reason. I read that it could be anything from a low battery, bad door sensor, or low alarm battery. The car starts up fine in the coldest weather and the alarm is loud and strong.

Personally, I don't want the alarm anyway and want to disable it. I read that on the 2003's, you can pull the #8 fuse in the engine compartment to do this.

My question is: is this the same for a 2005? Will anything else be disabled by pulling the fuse? Or is there a better way?

there is info about which fuse does what in the owner's manual and/or the sheet in the interior fuse compartment (see manual for how to access).

yes, i got a hold of the fuse diagram and it states that the #8, #9 and #41 fuses all work with the alarm. i pulled the #8 fuse, which had been advised in a previous thread for a 2003, but now the remote locks don't work because they operate on the same #8 fuse.

The following is more work. However, this will have no negative effect on any other component in the car. Open the wheel well liner of the front passenger wheel and disconnect the connector for the alarm.

disconnecting the horn as suggested is probably the easiest way to deal with it. there are probably DIP switches somewhere which will lower the sensitivity of the glass breakage or motion sensor or disable door sensors, etc. but you would need to ask a dealer tech where to find them (no mention of alarm in the haynes manual). you would not want to lose the ignition lock feature of the system because unlike a noisy alarm, it actually prevents theft.